MAB@CORNELLC.CCS.CORNELL.EDU (Mark Bodenstein) (03/22/88)
Network World, in their March 14 issue, published an article about GOSIP, and the conversion from TCP/IP to ISO protocols. In brief, they say that ISO OSI is in the process of becoming a government standard, supplanting TCP/IP, but that the conversion may take a very long time. At the end of the article, they give an analogy to the conversion from NCP to TCP, from Kevin Ebel of DCA, and say, in effect, that the difference between the two conversions is only one of scale. Let's assume, for the purpose of non-argument, that the analogy is apt. (I don't think it is.) Does anyone know what the difference in scale is, between these two conversions? How many NCP hosts and routers/gateways/ imps were there at the time of conversion to TCP? And how many TCP hosts and routers/gateways/imps are there now and/or will there be two years from now (assuming that to be the time of the beginning of the TCP->OSI conversion)? Mark Bodenstein (mab@cornellc.ccs.cornell.edu) Cornell University
swb@DEVVAX.TN.CORNELL.EDU (Scott Brim) (03/23/88)
You know, NCP is still alive and well in certain sheltered parts of the world.
BILLW@MATHOM.CISCO.COM (William Westfield) (03/23/88)
Does anyone know what the difference in scale is, between these
two conversions? How many NCP hosts and routers/gateways/ imps
were there at the time of conversion to TCP? And how many TCP
hosts and routers/gateways/imps are there now and/or will there
be two years from now (assuming that to be the time of the
beginning of the TCP->OSI conversion)?
I still have an "I Survived the TCP Transition" button somewhere, so
Ill take a shot at this...
The conversion from NCP to TCP took place on 1-Jan-1983. It was about
6 months after that that most hosts could communicate with each other.
As of the cut-over data, most vendor software wasn't quite ready...
My March, 1982 Arpanet directory shows 96 imps, and about 300 hosts.
(And there were more DEC-20s than there were vaxen.)
NCP didn't incorporate ideas like "routers" or "internet". There was
just the ARPAnet. If you had a local area network, it was probably a
Xerox "experimental" 3Mb ethernet, and it probably spoke PUP protocols.
The current NIC host table has 854 Networks, 456 gateways (routers),
and 5719 hosts in it. This, of course, does not include isolated
places that have set up IP networks without being assigned network
numbers by the NIC. It probably does not include gateways that aren't
involved with talking to the arpanet. It does not include subnet
gateways used within an autonomous system. It does not include hosts
whose names are only obtainable only via the domain system. I think
current estimates are that one new network is added to the Internet
every working day (eg 250/year).
Hopefully, there will be a several year period during which ISO
protocols and TCP/IP will co-exist, and eventually, one of them will
become unused.
Bill Westfield
cisco Systems.
-------CERF@A.ISI.EDU (03/23/88)
I can't give firm numbers but there were on the order of 20-25 different operating system implementations of NCP and somewhat fewer for TCP at the time the conversion was done - some hosts never made the change and were simply retired (good excuse...). The NCP/TCP and TCP/ISO analogies are not exact. For one thing, NCPwas never a commercial product. TCP is. For another, only ARPANET hosts did NCP because that was NOT an internet protocol, so a single administration could insist on the conversion and was even able to turn off NCP capability within the subnet as a forcing function. This is not possible for TCP/ISO except perhaps at the gateways (and maybe for the subnets if packet types for ISO IP and DoD IP are distinct, as I suppose they are likely to be). There must be literally tens of thousands of TCP/IP hosts by now compared to at most a couple of hundred NCP hosts in Jan 83. Somehow I think the analogy is not very apt. Vint
LYNCH@A.ISI.EDU (Dan Lynch) (03/23/88)
Scott, You missed the chance to say "NCP is still alive in a well..." Yes, NCP is still running in some classified environments where once you get something to run that you (somehow) trust, you leave it alone. As for the larger issue raised by Mark, moving from NCP tp TCP/IP was a large task, but it was ameliorated by the relatively small number of hosts affected. In those days there were probably only a thousand hosts and ten system types to deal with. It took a good amount of coordination to get those hosts to all bring their software "forward" to permit testing before we threw the switch on jan 1, 1983. When we go to make the change to OSI there will be a few million hosts on hundreds of system types out there and there will be no "authority" to tell everyone to switch. So, Mark, you are quite right to be "worried" that a conversion might take longer, be harder, etc. Dan -------